The National Security Agency has spent years demanding that companies turn over their data. Now, the spy agency finds the shoe is on the other foot. A defendant in a Florida murder trial says telephone records collected by the NSA as part of its surveillance programs hold evidence that would help prove his innocence, and his lawyer has demanded that prosecutors produce those records.

On Wednesday, the federal government filed a motion saying it would refuse, citing national security. But experts say the novel legal argument could encourage other lawyers to fight for access to the newly disclosed NSA surveillance database.

“What’s good for the goose is good for the gander, I guess,” said George Washington University privacy law expert Dan Solove. “In a way, it’s kind of ironic.”

Defendant Terrance Brown is accused of participating in the 2010 murder of a Brinks security truck driver. Brown maintains his innocence, and claims cellphone location records would show he wasn’t at the scene of the crime. Brown’s cellphone provider — MetroPCS — couldn’t produce those records during discovery because it had deleted the data already.